1. Field of the Invention
This invention relates to a compression refrigerating machine utilizing a refrigerant not containing a Cl radical.
2. Description of the Prior Art
In a compression refrigerating machine that utilizes a refrigerant such as CFC11, CFC12, HCFC123, HCFC22 or the like containing a Cl radical, even if a mineral oil (e.g a turbine oil) used as a lubricating oil for a compressor is released to the atmosphere, the moisture absorptivity of water content is minimal, so that it has been unnecessary to provide with means for removing water content particularly in the oil. However, a so-called alternative refrigerant that replaces the above-mentioned refrigerant and does not contain a Cl radical, for example, HFC134a (1,1,1,2 tetrafluoroethane), is not dissolvable with a mineral oil and, because of their two-phase separation, the mineral oil cannot be used in a compression refrigerating machine. Accordingly, it becomes indispensable to use a synthetic oil (e.g. an ester oil) newly designed molecularly to acquire a mutual solubility.
Nonetheless, the above-mentioned synthetic oil has a nature tending to absorb moisture or water content and, when admixed with a large amount of water, is hydrolyzed and hence fails to function as a lubricating oil. Moreover, the synthetic oil is unstable with respect to a chloride and, when admixed with a large amount of chlorine content, is hydrolyzed and hence again fails to function as a lubricating oil. Furthermore, water content is generally admixed with a lubricating oil when water, used prior to an operation of the compression refrigerating machine during an airtight test, is not completely removed and remains in the compression refrigerating machine. And when a synthetic oil is used, there is a tendency that this water residue is easily mixable patentably with a synthetic oil.
Also, when a compression refrigerating machine, at the time of its assembly, is washed with a chlorine containing detergent and, if the detergent is not completely removed after the washing step, a synthetic oil is generally unstable with respect to a chloride and, when mixed with chlorine, is hydrolyzed and the water is increasingly deteriorated resulting in significantly reducing the function of the lubricating oil.